@dpiponi @BartoszMilewski @dougmerritt @johncarlosbaez Quote posting here to continue along this line of discussion without derailing @johncarlosbaez's original thread.
I agree that clearly every interpretation of QM has difficulties, otherwise there would be consensus on the matter. I guess I would hope that none of the views are held with religious fervor. 🙂
I will say that I have never found the criticism of MWI on the basis of Occam's razor convincing. I'll agree that the exact meaning of parsimony is somewhat debatable, but it's generally considered to apply to the simplicity of assumptions, not conclusions. MWI arguably simplifies assumptions, doing away with von Neumann's process 1 (state reduction), at the cost of leading to the conclusion that there should be many parallel branches of the Universe's wavefunction.
I think the more cogent criticisms are about the derivation of the Born rule and meaning of probabilities in this interpretation. Still, I find this to be less dissatisfying than the orthodox interpretation, and I think it fits in a bit more naturally with understanding environmentally-induced decoherence as the mechanism for the emergence of classical dynamics.
QT: https://mathstodon.xyz/@dpiponi/112838797541954778
Well, it seems like I failed in my attempt not to derail things. Sorry @johncarlosbaez!
@johncarlosbaez Ironically, being the cause of the distraction, I thought it was a quite interesting question. What you said certainly sounds plausible, asymmetry can often arise in an open quantum system via decoherence of a symmetric superposition. It seems to me that I've heard people refer to the inhomogeneities in the CMBR being the signature of pre-inflationary quantum fluctuations, but I don't think I've ever heard any discussion that talked very rigorously about how they arise, as far as the quantum state and decoherence mechanism.
On the latter point, all the decoherence would require is that the stress energy tensor coarse grained over astronomical distance scales be couple to other degrees of freedom.
@internic - thanks. I'm getting fascinated by this question; I will ask some people about it!
@internic - that's okay. People here clearly find it more fun to talk about interpretations of quantum mechanics than figure out whether an initially perfectly homogeneous state is compatible with the inhomogeneities we find in our Universe today. And maybe that's no surprise: I'm having a lot of trouble finding any discussion of the latter question. The closest I can get is people talking about the power spectrum of inhomogeneities in the inflationary era, whether it's Gaussian, etc.